It's a fun mode, I enjoy it a lot! One of the nicest things about it is that you play with agents you don't usually pick. I guess most of us are indifferent about what character to unlock next, so having every agent available would be aweso...

Passive: Forge starts the game with 250 metal and can melt down weapons dropped by enemies to get 40% of that weapons cost worth of metal. Metal is reset when sides are switched. Forge can use any ability that she has used this round again...